/**
 * Copyright (c) 2007-2012, Timothy Stack
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 * * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * * Neither the name of Timothy Stack nor the names of its contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @file listview_curses.hh
 */

#ifndef listview_curses_hh
#define listview_curses_hh

#include <cstdint>
#include <list>
#include <string>
#include <utility>
#include <vector>

#include <sys/types.h>

#include "base/attr_line.hh"
#include "hasher.hh"
#include "mapbox/variant.hpp"
#include "view_curses.hh"
#include "vis_line.hh"

class listview_curses;

/**
 * Data source for lines to be displayed by the listview_curses object.
 */
class list_data_source {
public:
    virtual ~list_data_source() = default;

    /** @return The number of rows in the list. */
    virtual size_t listview_rows(const listview_curses& lv) = 0;

    virtual size_t listview_width(const listview_curses& lv) { return INT_MAX; }

    /**
     * Get the string value for a row in the list.
     *
     * @param row The row number.
     * @param value_out The destination for the string value.
     */
    virtual void listview_value_for_rows(const listview_curses& lv,
                                         vis_line_t start_row,
                                         std::vector<attr_line_t>& rows_out)
        = 0;

    virtual size_t listview_size_for_row(const listview_curses& lv,
                                         vis_line_t row)
        = 0;

    virtual bool listview_is_row_selectable(const listview_curses& lv,
                                            vis_line_t row)
    {
        return true;
    }

    virtual void listview_selection_changed(const listview_curses& lv) {}
};

class list_gutter_source {
public:
    virtual ~list_gutter_source() = default;

    virtual void listview_gutter_value_for_range(const listview_curses& lv,
                                                 int start,
                                                 int end,
                                                 const char*& ch_out,
                                                 role_t& role_out,
                                                 role_t& bar_role_out)
    {
        ch_out = NCACS_VLINE;
    }
};

class list_overlay_source {
public:
    virtual ~list_overlay_source() = default;

    virtual void reset() {}

    enum class media_t : uint8_t {
        display,
        file,
    };

    virtual bool list_static_overlay(const listview_curses& lv,
                                     media_t media,
                                     int y,
                                     int bottom,
                                     attr_line_t& value_out)
    {
        return false;
    }

    virtual std::vector<attr_line_t> list_overlay_menu(
        const listview_curses& lv, vis_line_t line)
    {
        return {};
    }

    virtual std::optional<attr_line_t> list_header_for_overlay(
        const listview_curses& lv, vis_line_t line)
    {
        return std::nullopt;
    }

    virtual void list_value_for_overlay(const listview_curses& lv,
                                        vis_line_t line,
                                        std::vector<attr_line_t>& value_out)
    {
    }

    virtual void set_show_details_in_overlay(bool val) {}

    virtual bool get_show_details_in_overlay() const { return false; }

    struct menu_item {
        menu_item(vis_line_t line,
                  line_range range,
                  std::function<void(const std::string&)> action)
            : mi_line(line), mi_range(range), mi_action(std::move(action))
        {
        }

        vis_line_t mi_line;
        line_range mi_range;
        std::function<void(const std::string&)> mi_action;
    };
    std::vector<menu_item> los_menu_items;
};

class list_input_delegate {
public:
    virtual ~list_input_delegate() = default;

    virtual bool list_input_handle_key(listview_curses& lv, const ncinput& ch)
        = 0;

    virtual void list_input_handle_scroll_out(listview_curses& lv) {}
};

/**
 * View that displays a list of lines that can optionally contain highlighting.
 */
class listview_curses
    : public view_curses
    , log_state_dumper {
public:
    using action = std::function<void(listview_curses*)>;

    listview_curses();

    listview_curses(const listview_curses&) = delete;
    listview_curses(listview_curses&) = delete;

    void deinit() override
    {
        view_curses::deinit();
        this->lv_overlay_source = nullptr;
    }

    /** @param src The data source delegate. */
    void set_data_source(list_data_source* src)
    {
        this->lv_source = src;
        this->invoke_scroll();
        this->reload_data();
    }

    /** @return The data source delegate. */
    list_data_source* get_data_source() const { return this->lv_source; }

    void set_gutter_source(list_gutter_source* src)
    {
        this->lv_gutter_source = src;
    }

    /** @param src The data source delegate. */
    listview_curses& set_overlay_source(list_overlay_source* src)
    {
        this->lv_overlay_source = src;
        this->reload_data();

        return *this;
    }

    /** @return The overlay source delegate. */
    list_overlay_source* get_overlay_source() const
    {
        return this->lv_overlay_source;
    }

    listview_curses& add_input_delegate(list_input_delegate& lid)
    {
        this->lv_input_delegates.push_back(&lid);

        return *this;
    }

    /**
     * @param va The action to invoke when the view is scrolled.
     * @todo Allow multiple observers.
     */
    void set_scroll_action(action va) { this->lv_scroll = std::move(va); }

    void set_show_scrollbar(bool ss) { this->lv_show_scrollbar = ss; }

    bool get_show_scrollbar() const { return this->lv_show_scrollbar; }

    void set_show_bottom_border(bool val)
    {
        if (this->lv_show_bottom_border != val) {
            this->lv_show_bottom_border = val;
            this->set_needs_update();
        }
    }
    bool get_show_bottom_border() const { return this->lv_show_bottom_border; }

    void set_selectable(bool sel)
    {
        this->lv_selectable = sel;
        this->vc_needs_update = true;
    }

    bool is_selectable() const { return this->lv_selectable; }

    void set_ensure_selection(bool val) { this->lv_ensure_selection = val; }

    bool get_ensure_selection() const { return this->lv_ensure_selection; }

    void set_selection(vis_line_t sel);

    void set_selection_without_context(vis_line_t sel);

    enum class shift_amount_t {
        up_line,
        up_page,
        down_line,
        down_page,
    };

    void shift_selection(shift_amount_t sa);

    std::optional<vis_line_t> get_selection() const
    {
        if (this->lv_selectable) {
            if (this->lv_selection == -1) {
                return std::nullopt;
            }
            return this->lv_selection;
        }
        return this->lv_top;
    }

    void set_show_details_in_overlay(bool val);

    std::optional<vis_line_t> get_overlay_selection() const
    {
        if (this->lv_overlay_focused) {
            return this->lv_focused_overlay_selection;
        }

        return std::nullopt;
    }

    void set_overlay_selection(std::optional<vis_line_t> sel);

    void set_sync_selection_and_top(bool value)
    {
        if (this->lv_sync_selection_and_top != value) {
            this->lv_sync_selection_and_top = value;
            this->set_needs_update();
        }
    }

    listview_curses& set_word_wrap(bool ww);

    bool get_word_wrap() const { return this->lv_word_wrap; }

    enum row_direction_t {
        RD_UP = -1,
        RD_DOWN = 1,
    };

    vis_line_t rows_available(vis_line_t line, row_direction_t dir) const;

    struct layout_result_t {
        vis_line_t lr_actual_height{0_vl};
        vis_line_t lr_desired_row{0_vl};
        std::vector<vis_line_t> lr_above_line_heights;
        vis_line_t lr_desired_row_height{0_vl};
        std::vector<vis_line_t> lr_below_line_heights;
    };

    layout_result_t layout_for_row(vis_line_t row) const;
    vis_line_t height_for_row(vis_line_t row,
                              vis_line_t height,
                              unsigned long width) const;

    template<typename F,
             typename R = std::invoke_result_t<F, const attr_line_t&>>
    auto map_top_row(F func) const -> R
    {
        if (this->lv_top >= this->get_inner_height()) {
            if constexpr (std::is_same_v<R, void>) {
                return;
            } else {
                return std::nullopt;
            }
        }

        std::vector<attr_line_t> top_line{1};
        auto sel = this->get_selection();
        if (!sel) {
            if constexpr (std::is_same_v<R, void>) {
                return;
            } else {
                return std::nullopt;
            }
        }

        this->lv_source->listview_value_for_rows(*this, sel.value(), top_line);
        return func(top_line[0]);
    }

    /**
     * Set the line number to be displayed at the top of the view.  If the
     * value is invalid, flash() will be called.  If the value is valid, the
     * new value will be set and the scroll action called.
     *
     * @param top The new value for top.
     * @param suppress_flash Don't call flash() if the top is out-of-bounds.
     */
    void set_top(vis_line_t top, bool suppress_flash = false);

    /** @return The line number that is displayed at the top. */
    vis_line_t get_top() const { return this->lv_top; }

    std::optional<vis_line_t> get_top_opt() const
    {
        if (this->get_inner_height() == 0_vl) {
            return std::nullopt;
        }

        return this->lv_top;
    }

    /** @return The line number that is displayed at the bottom. */
    vis_line_t get_bottom() const;

    vis_line_t get_top_for_last_row();

    void set_top_for_last_row() { this->set_top(this->get_top_for_last_row()); }

    void set_selection_to_last_row();

    /** @return True if the given line is visible. */
    bool is_line_visible(vis_line_t line) const
    {
        return this->get_top() <= line && line <= this->get_bottom();
    }

    /**
     * Shift the value of top by the given value.
     *
     * @param offset The amount to change top by.
     * @param suppress_flash Don't call flash() if the offset is out-of-bounds.
     * @return The final value of top.
     */
    vis_line_t shift_top(vis_line_t offset, bool suppress_flash = false);

    /**
     * Set the column number to be displayed at the left of the view.  If the
     * value is invalid, flash() will be called.  If the value is valid, the
     * new value will be set and the scroll action called.
     *
     * @param left The new value for left.
     */
    void set_left(int left);

    /** @return The column number that is displayed at the left. */
    int get_left() const { return this->lv_left; }

    /**
     * Shift the value of left by the given value.
     *
     * @param offset The amount to change top by.
     * @return The final value of top.
     */
    int shift_left(int offset);

    /**
     * Set the height of the view.  A value greater than one is considered to
     * be an absolute size.  A value less than or equal to zero makes the
     * height relative to the size of the enclosing window.
     *
     * @height The new height.
     */
    void set_height(vis_line_t height)
    {
        if (this->lv_height != height) {
            this->lv_height = height;
            this->set_needs_update();
        }
    }

    /** @return The absolute or relative height of the window. */
    vis_line_t get_height() const { return this->lv_height; }

    /** @return The number of rows of data in this view's source data. */
    vis_line_t get_inner_height() const
    {
        return vis_line_t(this->lv_source == nullptr
                              ? 0
                              : this->lv_source->listview_rows(*this));
    }

    size_t get_inner_width() const
    {
        return this->lv_source == nullptr
            ? 0
            : this->lv_source->listview_width(*this);
    }

    void set_overlay_needs_update() { this->lv_overlay_needs_update = true; }

    /**
     * Get the actual dimensions of the view.
     *
     * @param height_out The actual height of the view in lines.
     * @param width_out The actual width of the view in columns.
     */
    void get_dimensions(vis_line_t& height_out, unsigned long& width_out) const;

    std::pair<vis_line_t, unsigned long> get_dimensions() const
    {
        unsigned long width;
        vis_line_t height;

        this->get_dimensions(height, width);
        return std::make_pair(height, width);
    }

    /** This method should be called when the data source has changed. */
    virtual void reload_data();

    bool handle_key_using_delegates(const ncinput& ch);

    /**
     * @param ch The input to be handled.
     * @return True if the key was eaten by this view.
     */
    bool handle_key(const ncinput& ch);

    /**
     * Query the data source and draw the visible lines on the display.
     */
    bool do_update() override;

    bool handle_mouse(mouse_event& me) override;

    std::optional<view_curses*> contains(int x, int y) override;

    listview_curses& set_head_space(vis_line_t space)
    {
        this->lv_head_space = space;

        return *this;
    }

    vis_line_t get_head_space() const { return this->lv_head_space; }

    listview_curses& set_tail_space(vis_line_t space)
    {
        this->lv_tail_space = space;

        return *this;
    }

    vis_line_t get_tail_space() const { return this->lv_tail_space; }

    virtual void update_hash_state(hasher& h) const;

    void log_state() override;

    virtual void invoke_scroll() { this->lv_scroll(this); }

    struct main_content {
        vis_line_t mc_line;
        size_t mc_wrapped_line;
        line_range mc_line_range;
    };
    struct static_overlay_content {};
    struct overlay_menu {
        vis_line_t om_line;
    };
    struct overlay_content {
        vis_line_t oc_main_line;
        vis_line_t oc_line;
        vis_line_t oc_height{0};
        vis_line_t oc_inner_height{0};
    };
    struct empty_space {};

    using display_line_content_t = mapbox::util::variant<main_content,
                                                         overlay_menu,
                                                         static_overlay_content,
                                                         overlay_content,
                                                         empty_space>;

    int get_y_for_selection() const;

    std::optional<role_t> lv_border_left_role;

protected:
    void delegate_scroll_out()
    {
        for (auto& lv_input_delegate : this->lv_input_delegates) {
            lv_input_delegate->list_input_handle_scroll_out(*this);
        }
    }

    void update_top_from_selection();

    vis_line_t get_overlay_top(vis_line_t row,
                               size_t count,
                               const std::vector<attr_line_t>& total);
    vis_line_t get_overlay_height(size_t total, vis_line_t view_height) const;

    enum class lv_mode_t {
        NONE,
        DOWN,
        UP,
        DRAG
    };

    static list_gutter_source DEFAULT_GUTTER_SOURCE;

    list_data_source* lv_source{nullptr}; /*< The data source delegate. */
    std::list<list_input_delegate*> lv_input_delegates;
    list_overlay_source* lv_overlay_source{nullptr};
    action lv_scroll; /*< The scroll action. */
    vis_line_t lv_top{0}; /*< The line at the top of the view. */
    int lv_left{0}; /*< The column at the left of the view. */
    vis_line_t lv_height{0}; /*< The abs/rel height of the view. */
    bool lv_overlay_focused{false};
    vis_line_t lv_focused_overlay_top{0_vl};
    vis_line_t lv_focused_overlay_selection{0_vl};
    int lv_history_position{0};
    bool lv_overlay_needs_update{true};
    bool lv_show_scrollbar{true}; /*< Draw the scrollbar in the view. */
    bool lv_show_bottom_border{false};
    list_gutter_source* lv_gutter_source{&DEFAULT_GUTTER_SOURCE};
    bool lv_word_wrap{false};
    bool lv_selectable{false};
    vis_line_t lv_selection{-1_vl};
    bool lv_ensure_selection{false};
    bool lv_sync_selection_and_top{false};

    timeval lv_mouse_time{0, 0};
    int lv_scroll_accel{1};
    int lv_scroll_velo{0};
    int lv_mouse_y{-1};
    lv_mode_t lv_mouse_mode{lv_mode_t::NONE};
    vis_line_t lv_head_space{1_vl};
    vis_line_t lv_tail_space{1_vl};

    vis_line_t lv_display_lines_row{0_vl};
    std::vector<display_line_content_t> lv_display_lines;
    int lv_scroll_top{0};
    int lv_scroll_bottom{0};
};

#endif
